The objective of this proposal is to provide the applicant with exemplary research training in orthopedic bioengineering. To achieve this objective, a training regimen has been developed, consisting of research aims and substantial training activities. Degenerative rotator cuff disease affects greater than 50% of the aged population, leading to serious impairment of joint function and overall reduced quality of life. While external compression of the rotator cuff tendons is thought to contribute to the progression and pathogenesis of rotator cuff damage, the mechanism by which this occurs and the role of aging in this process is unknown. The overall objective of the studies proposed is to determine the baseline ability of mature and aged tendons to respond to compressive loading and to understand the consequences of an increased compressive loading environment on tendon function. The project outlined in the proposal combines work of fundamental basic research importance with work directed toward the future diagnosis and therapeutic treatment of early stage tendon degeneration. Overall, the project is designed to effectively train the applicant to develop the technical skills needed to establish a successful and independent research program in the future.